1. Field of the Invention
The present invention relates in general to devices for controlling the population of rodents in buildings and more specifically relates to an improved rodent control device that produces a pulsating and interrupted frequency resulting in an offensive magnetic field generation that acts as an irritant to rodents.
2. Description of the Prior Art
A wide variety of rodent control devices are known in the art. Many such devices operate on the basis of producing a low frequency of approximately 60 cycles per minute which is known in the art to be offensive to rodents such as rats and mice. For purposes of efficiency and long life operation, it has been found that the frequency generated does not have to be continuous, but instead, these devices operate effectively in spite of an interruption of the frequency at predetermined intervals. To provide the required frequency and the predetermined interruptions, the majority of prior art devices have employed a wide array of mechanical switching type devices requiring relatively frequent maintenance or replacement.
One improvement to the above devices is a unit that utilizes electronic switching components as disclosed in U.S. Pat. No. 4,414,653 issued Nov. 8, 1983. As described in the "653" Patent, the disclosed unit is designed to be utilized with a three wire electrical wiring system whereby the electrical wiring ground line serves as the path of conductive flow for the frequency generated by the unit.
A second improvement to the above devices is disclosed in U.S. patent application Ser. No. 06/787,490 which provides a control device adapted to be employed with common two wire electrical wiring systems found in most buildings and utilizes circuitry including an isolating means to electrically separate low and high voltage portions of the circuit to provide a more efficient and safety oriented type of circuitry.
The present invention is an improvement over the invention disclosed in the "490" Application. It is adapted to provide a simplified and more efficient circuit than that disclosed in such application.